The Portuguese boss is cautious of Morocco and Iran despite believing that his side and Spain will be favourites in their 2018 World Cup group

Fernando Santos acknowledged European champions Portugal and 2010 World Cup winners Spain should be considered the favourites in Group B, though he refused to underestimate Morocco and Iran.

Portugal and neighbouring Spain will go head-to-head at the World Cup in Russia next year, along with Morocco and Iran following Friday's draw.

Cristiano Ronaldo's Portugal – who claimed Euro 2016 – and Spain headline the group but Santos is wary of of the threat from the the other two sides, who made it through their respective CAF and AFC qualifying campaigns undefeated.

Santos added: "Morocco have scored goals and conceded none. This shows the strength of the team, there are players who have already played in Portugal, [Mehdi] Benatia who played for Juventus, and the quality of the coach.

"Iran had a good qualifying campaign, the second time they are in the World Cup, have experience and the coach also, maybe one of the most experienced of this World Cup. Also had a good performance, no defeat, conceded goals only in the last game when it was already qualified. It's going to be a difficult tournament."

Portugal and Spain will face-off at Fisht Olympic Stadium in Sochi on June 15, while Morocco and Iran clash in Saint Petersburg.